Node.js - xerocrypt/Misc GitHub Wiki
Server-Side JavaScript Framework, or a JavaScript runtime environment. Node.js was introduced in 2009/2010, but is already widely used and well-supported.
The main purpose of Node.js is to enable the creation of Web servers and associated network tools using JavaScript, and there are additional modules for performing server-side operations. Node.js enables communication between the client-side JavaScript and the server.
A Node.js application has the following:
- Module imports
- Server creation
- Response
Creating a Simple Server The server-side code for this is simple. First line imports the http module:
var http = require("http");
The following lines create the server using createServer(). Within this, we want to define the server response for client browsers starting a session on port 8090:
http.createServer(function (request, response)
{
`response.writeHead(200, {'Content-Type': 'text/plain'});`
`response.end('Hello World\n');`
}).listen(8090);
Also, we might want a response sent to the command line to indicate the server is started:
console.log('Server running at http://127.0.0.1:8090/');
File Operations
Perhaps the main reason we want server-side code, rather than something entirely client-based is data persistence - storing and retrieving data on a server is a core feature of a Web application.
Here I have two files: file-op.js server-side script, and the serverdata.txt data file. The latter simply contains two lines of text.
This time we import both the http and filesystem (fs) modules:
var http = require("http");
var fs = require("fs");
And specify the file to read:
var data = fs.readFileSync('serverdata.txt');
And this time, the HTTP response is defined as the contents of serverdata.txt:
http.createServer(function (request, response)
{
`response.writeHead(200, {'Content-Type': 'text/plain'});`
`response.end(data.toString());`
}).listen(8090);